The present invention relates generally to electronic appliance controllers and, more particularly, to electronic control systems which are independent of the type of appliance, which are internally restructurable to suit different appliance operating modes and which include programmable test mode capabilities likewise adaptable to different appliances, and which are automatically adaptable to different appliances.
Several aspects of the electronic control system disclosed herein are disclosed in greater detail in concurrently-filed application Ser. No. 07/969,139, filed, Oct. 30, 1992, by Steven A. Rice, Thomas R. Payne and William W. Wead entitled "Appliance Electronic Control System with Programmable Parameters Including Programmable and Reconfigurable Fuzzy Logic Controller", and in concurrently-filed application Ser. No. 07/968,831 filed Oct. 30, 1992, by Thomas R. Payne, Steven A. Rice and William W. Wead, entitled "Electronic Laundry Control with Fill Time Compensation", the entire disclosures of which are hereby expressly incorporated by reference.
The invention is disclosed herein in the context of an electronic control system for a family of commercial laundry products. In particular, the disclosed embodiment of the appliance electronic control system is applicable to each of a two-speed clothes washer, a one-speed clothes washer, an electric dryer and a gas dryer. It will be appreciated, however, that this usage is exemplary only, and that the invention is applicable to a wide variety of appliances.
In conventional laundry appliances, electro-mechanical timers are employed. In one exemplary product line, three distinct electro-mechanical timers are employed, one for the two-speed washer, one for the one-speed washer, and a common timer design shared by the electric dryer and the gas dryer.
It is highly desirable that a single controller, typically microprocessor- or microcontroller-based, be able to handle a variety of different appliances. Reasons include cost and inventory control. Volume discounts may be pursued, and inventory cost decreased. Manufacturing is greatly simplified if only one controller need be manufactured and stocked, which can then be employed in any appliance desired. Similarly, subsequent repair is greatly simplified if a service technician can carry with him a single spare controller that will operate in a variety of different appliances, rather than having to stock or possibly special order a controller for a specific appliance.
The subject invention in one aspect relates to means for easily testing the functionality of a machine. On conventional machines, the electro-mechanical timer assembly has a rotatable shaft or dial that may be manually positioned to activate particular functional elements within the machine, such as motors and solenoids, to cause a particular machine action. When such an electro-mechanical timer is replaced by an electronic controller, without a ready means of manual positioning, it is highly desirable that a means for accomplishing such functional testing be included.
From a macroscopic perspective, a clothes washing machine and a clothes dryer include functional elements such as motors, heaters and solenoids which are energized for predetermined periods of time. A complete cycle comprises several states of control outputs for activating the functional elements and which are allowed to exist for various lengths of time. There is an exception, namely water solenoids which remain activated until a full condition is detected.
In a line of commercial laundry machines, both washers and dryers have similar requirements for controller output switching devices that operate at 120 VAC. The washer requires five switching devices, two of which must have high current capabilities. The dryer requires three high current switching devices, and two low current switches. The selector switch, needed for user cycle selection, in the case of the two-speed washer has three drive lines and one sense line. In the case of the single-speed washer and both dryers, the selector switch has two drive lines and one sense line. In addition, the washing machine has two identical switches, namely a lid switch and a pressure switch for detecting water level. Certain inputs unique to a commercial laundry application, such as coin box sense, service door sense and coin input, are identical on all machines. Likewise, certain electronic components are common, such as clocks, power supplies, and the like.
One approach would be to provide a part for each controller, such as a particular printed circuit board (PCB), which is unique to the particular model.
Another approach would be to provide a controller PCB which is modifiable in either the factory or field for the particular appliance. For example, configuration jumper blocks, other forms of selectable jumpers, or encoding diodes might be provided. One common approach in providing configuration jumpers in general is to initially manufacture a PCB with jumpers or encoding diodes installed in all possible positions such that an installer can simply cut out selected ones to in effect program a particular binary code.
These approaches have drawbacks, however. In any case, additional time is required. Instructions must be provided and maintained, particularly by field service personnel. If an assembly error were to be made, the controller would attempt to operate the machine in a manner not consistent with the machine type.